21
3. Troubleshooting Guide
A. LED doesn’t light.
Check Power Voltage (TP1:3.3V, TP2:12V)
Reference Voltage
[TP5:V13(1.3V) and GND.]
Does “H” output in IC501 pin ?
Check and replace R705, R706, Q701
and LED701 (LED703 for DELL).
Is the CLOCK Frequency of
IC501 pin 33.86MHz?
Check the power input
pattern.
Check IC501.
Check and replace
X501; 33.86MHz.
Is the CLOCK Frequency of IC501 pin
33.86MHz?
Check and replace IC501.
YES
OK
NG
YES
YES
NO
NO
NO
37
54
54
A-1
A-1